|VANLOOCKE, ANDY - Iowa State University|
Submitted to: Annual Reviews of Plant Biology
Publication Type: Literature Review
Publication Acceptance Date: 11/30/2015
Publication Date: 1/15/2016
Citation: Walker, B.J., VanLoocke, A., Bernacchi, C.J., Ort, D.R. 2016. The costs of photorespiration to food production now and in the future. Annual Reviews of Plant Biology. 67:107-129.
Interpretive Summary: Photorespiration is essential for plants to grow in atmospheres with oxygen, but requires a massive amount of energy and loses carbon from the plant. This review covers what drives photorespiration under field conditions and estimates how much yield loss can be attributed to photorespiration in the Midwest for soybeans and wheat.
Technical Abstract: Photorespiration is essential for C3 plants, but operates at the massive expense of fixed carbon dioxide and energy. Photorespiration is initiated when the initial enzyme of photosynthesis, Rubisco, reacts with oxygen instead of carbon dioxide and produces a toxic compound which is recycled by photorespiration. Rubisco kinetics constrain models of leaf photosynthesis which explore gas exchange and energy use. These leaf-level models are coupled with the impact of environmental conditions to produce canopy and regional-scale models which can be used to determine the cost of photorespiration under current and future atmospheres. A regional scale model reveals that photorespiration currently decreases United States soybean and wheat yields by 36 and 20 percent. Additionally, a 5 percent decrease in the losses due to photorespiration would be worth ~$500 million annually in the United States. While photorespiration is tied to other important metabolic functions, the benefit of improving its efficiency appears to outweigh potential disadvantages.